The Laser Polarization Modulation And Adaptive Light Stability Technology Based On Liquid Crystal

Atmospheric laser communication is a information transmission energy system that carrier is the laser.It will be interfered by the atmospheric attenuation and turbulence,which will increase system BER when the laser is transmitted through atmosphere.The laser beam will arise some exceptional phenomenon,such like strong scintillation and so on,which will lead ystem instability in the laser energy beacon road receiver,and then a decline in the quality of communication,the bit error rate of the system increased,and even the emergence of communication interruption especially when the laser propagation in the atmospheric turbulence vortex.Aiming at the problem of energy scintillation caused by atmospheric turbulence,I study the laser polarization modulation and adaptive stabilization technology based on liquid crystal light in this paper,design a liquid crystal variable retarder polarization modulation of the laser to achieve the attenuation controlation of laser energy intensity control system and realize the adaptive controlation of the intensity of the incident laser,which makes the laser energy receiving system to keep stable.In this thesis,I use electrically controlled birefringence of liquid crystal to change the alignment of liquid crystal molecules deployed by LCVR at both ends of the voltage,which thus changes the refractive index,which leads the incident laser will has a phase delay and then realizes the polarization modulation on incident laser.Based on the above-mentioned,I make a liquid crystal light modulator which consist of LCVR,polarizing piece and analyzer sheet and exploit the liquid crystal adaptive microcontroller that the core is single chip computer to change the liquid crystal light debugger's driving voltage,which changes the transmittance and implement the closed-loop control of laser intensity further.Finally It will achieve the adaptive stabilization the effect of light.The experimental results show that the laser polarization modulation and adaptive liquid crystal light stability technology in atmospheric laser communication system based on communication can improve the anti-interference ability and enhance the stability of the system,greatly enhance the quality of the communication system.When the laser is transmitted in the atmosphere,low speed and high reliability laser communication can also be realized.